1. Field of the Invention
The present invention relates to an arrangement for connecting a ceramic rotor wheel, particularly the turbine rotor wheel of a turbomachine, such as a gas turbine engine, to a metallic shaft, in which the connection is formed between a shaft journal of the ceramic rotor wheel and a tubular end portion of the metallic machine shaft which is mounted thereon.
2. Discussion of the Prior Art
In presently proposed or currently known arrangements of the above-mentioned type, relatively considerable difficulties are still encountered in the design of a suitable, positive interconnection between the respective metallic machine shaft and a ceramic rotor wheel, particularly a turbine rotor wheel.
Consequently, for this purpose, there have been proposed shrink-fitted connections, adhesive connections, or even soldered connection. However, on the other hand, because of the extremely different material properties and structures of ceramic components, and on the other hand, those of the metallic components, and because of the widely differing coefficients of thermal expansion involved in these connections and the stresses in the materials resulting therefrom, it has heretofore not been possible to obtain a satisfactory result for such connections (metal-ceramic).
In addition thereto, connections of that type must be able to safely sustain the high speeds and temperatures associated with modern gas turbine engines in which, among other factors, there must be considered the centrifugal loads and stresses caused by the relatively high rotational speeds, particularly in the outer peripheral region of this connection.